Interlaboratory survey of the quality of urinary arsenic and thallium assays in the European community.

The present investigations were performed to assess the feasibility of an international round robin on biological samples, to assess the overall performance of toxicological laboratories in the European Community (EC) and the applicability of analytical methods used. Twelve laboratories representing 10 member countries within the Community, which could be considered to be well qualified for this type of work, participated in this study. The set-up chosen was that of a so-called long-term interlaboratory survey. It appeared that quality assurance by an international round robin is feasible within the EC. The samples consisted of arsenic and thallium, both at a high and a low level and the results of the individual laboratories as well as interlaboratory data are reported. In general, a good overall performance was seen, and the methods used showed acceptable accuracy and precision.